The study of the groundwater by using the 34S and 18O of the sulphates-S18O4 isotopes

The stable isotope of the sulphur atom (S-34) and the O-18 of the sulphates ((SO4)-O-18) give information about the type of the mineralisation of the groundwater existing during the water seepage. The decrease of the concentrations in dissolved SO42- (meq/L) versus the increase of delta O-18 (% vs. SMOW) of the sulphates ((SO42-)-O-18) confirms a partial reduction of the dissolved sulphates in the water. The Under-saturated waters versus the gypsum do not cause the precipitations of the sulphates. The study of delta S-34 (% CD) vs. Cl- (mg/L) indicates high variations in delta S-34 (% CD) for weak difference in the Cl- (mg/L) content, this is due to the reduction of the dissolved sulphates. Concerning the Jurassic water in Lebanon, an oxidation of the sulphide can take place. (C) 2014 Elsevier B.V.